A retaining system for retaining an individual against inertial forces while sitting in a seat of a vehicle includes a connecting element for deploying across the width of the rear surface of the seat back support, and two retaining straps, each attached to a side of the connecting element so as to provide a loop through which an arm of the individual can be inserted. A catch assembly is provided for releasable connecting between the two retaining straps so as to allow closure of the retaining system around the chest of the individual.